1. Field
This invention relates to means for ventilating and aspirating the respiratory tracts of medical patients. It is particularly directed to an improved ventilation circuit adapter.
2. State of the Art
Currently available means for ventilating and aspirating congested lungs and obstructed breathing passage ways may be classified as either "simple" or "complex." Devices of both classes have significant drawbacks and limitations. The available devices of simple construction tend to expose both the patient and the service provider to microbial contaminants. Although these devices are relatively less expensive, their use potentially provides dangerously inadequate patient ventilation during the aspirating procedure. More elaborate devices tend to be physically obstructive and economically prohibitive to use.
In common medical practice, a medical practitioner inserts a tracheal suctioning catheter into a medical patient's lungs. The catheter may be positioned within a tracheal tube, endotracheal tube or nasopharyngeal tube intubated at a tracheotomy incision, mouth or nasal opening, respectively. The end of the catheter accessible by the medical practitioner is regarded as its "proximal" end. The end of the catheter remote from the practitioner, that is, within the patient, is regarded as its "distal" end. In a typical procedure, negative pressure is exerted at the proximal end of the catheter. Undesired respiratory fluids and mucoid secretions are thereby evacuated from the medical patient through the distal end of the catheter.
In a relatively simple practice, a source of vacuum pressure remains attached to the proximal catheter end. Negative pressure is not communicated to the distal catheter end initially. Rather, negative pressure is communicated to an aperture near the proximal catheter end. When aspiration of the patient is desired, the practitioner plugs the aperture, normally with a finger or thumb. Negative pressure is thereby instantaneously diverted from the small aperture near the proximal catheter end through the catheter lumen to the distal end of the catheter. In this fashion, undesired respiratory fluids are aspirated from the respiratory tract of the patient. The suctioning catheter is then disconnected from the vacuum source and discarded after a single use.
Ventilation of the patient simultaneously with this aspirating procedure is generally impractical. Such ventilation inherently requires assistance from additional personnel as well as mechanical assistance, neither of which is available as a matter of course. Accordingly, the aspirating procedure must ordinarily be completed within a short period of time. Otherwise, the patient may experience oxygen deficiency and be exposed to the resulting potential for heart arrhythmia and/or failure.
More complex aspirating devices are available, which while avoiding some of the disadvantages attendant to the structurally more simple devices, impose additional disadvantages. For example, they are significantly more expensive to construct, and their greater number of moving parts increases the risk of disfunction during use. They are also larger and more cumbersome to use, imposing a greater physical interference with other, related procedures.
The complex, closed-system devices are characteristically comprised of a manifold structure enabling introduction of ventilating gases and intermittent exhalation of patient breath simultaneously with insertion and operation of the tracheal suctioning catheter. These systems almost universally involve at least one collapsible, plastic envelope entirely surrounding the catheter and purporting to provide a sterile barrier between the otherwise exposed external surface of the catheter and the ambient atmosphere. In practice, a practitioner manually externally collapses the envelope onto the external surface of the catheter and advances the catheter into the throat of a patient, retracting the catheter in a similar fashion following the aspiration procedure.
These closed-system devices under present medical protocol are ordinarily used at least hourly for up to 48 hours for each patient before being replaced. Problems attendant to such frequent and repeated in-dwelling use are numerous, among other problems constriction of the catheter lumen and valve flow path with dried and drying phlegm and other respiratory secretions, creation of contaminant-allowing pinholes in the collapsible plastic barrier and the need to physically move the lengthy and cumbersome devices from one location on the body of the patient to another when the devices interfere with other procedures. Associated with the dried and drying secretions inside the lumen are like secretions on the exterior of the catheter wall which accumulate at the manifold wiper seal; such thick and undesired respiratory secretions not only restrict the facile movement of the catheter through the manifold, but also can be unavoidably reintroduced to the patient in subsequent repeat procedures.
Material prior art structures and methods are described among other places in U.S. Pat. Nos. 5,133,345 to Lambert; 5,107,829 to Lambert; 5,083,561 to Russo; 5,065,754 to Jensen; 5,029,580 to Radford et al.; 5,025,806 to Palmer et al.; 4,981,466 to Lambert; 4,967,743 to Lambert; 4,938,741 to Lambert; 4,872,579 to Palmer; 4,838,255 to Lambert; 4,836,199 to Palmer; 4,834,726 to Lambert; 4,825,859 to Lambert; 4,805,611 to Hodgkins; 4,696,296 to Palmer; 4,638,539 to Palmer; 4,569,344 to Palmer; 4,327,723 to Frankhouser; and 3,991,762 to Radford.
Other closed-system, sterility preserving devices which involve sterile barriers formed of rubber-like materials and intended for penetration by rigid cannulae include: rubber like caps fitted on "y" injection site structures and located at the end of indwelling intravenous catheters, such as those distributed by HARMAC Medical Specialties, Inc. of Buffalo, N.Y. under the product number H1429104; rubber-like caps fitted on housing structure anchorable at injection sites, such as those distributed by Baxter Healthcare Corp. of Deerfield, Ill. under product number 2N3399 and their trademark "InterLink.TM.;" and threaded lock cannula used in conjunction with the Baxter InterLink.TM. for needleless injection by Becton Dickinson & Co. of Franklin Lakes, N.J. under product number 303369 and their trademark "InterLink.TM.."
U.S. Pat. No. 4,351,328 to Bodai discloses a method and apparatus for accomplishing endotracheal suctioning of a patient without the need for disconnecting the patient from a respirator. The disclosed apparatus permits the maintenance of positive end expiratory pressure without interruptions during suctioning. A notable feature of the device is the ease with which a suctioning tube may be removed from an associated ventilation manifold.
There remains a need for a ventilating and aspirating device, wherein a closed-system, multiple use manifold for a single patient is coupled with a single-patient, single use catheter, which structure is comprised of relatively few parts, is easily assembled and is not susceptible to disfunction.
Also, a need remains for a tracheal suctioning device which unobtrusively enables ongoing closed-system ventilation and repeated aspiration of a single patient without interim obstruction of peripheral procedures.